Muscle vs Strength: Does size really matter?

If we asked you to think of the strongest person in the world, you’d probably picture someone like Arnold Schwarzenegger in his glory days – someone with tree-trunk arms and ridiculous lats.

That might be an extreme example, but we often think muscle size equals strength… which is not necessarily true. To some degree, of course it is – but when it comes to comparing bodybuilders and weightlifters… it’s a very different story. So why is that?

Let’s break it down a little…

There are a number of factors that contribute to strength gains but we need to look at the different types of movements that activate different types of fibres in your muscles. There are several types of fibres in your muscles, but what’s relevant here is the difference between the two main ones – fast-twitch and slow-twitch.

Slow-twitch fibres are activated in slower movements or movements that require energy over time like endurance exercise. They’re much less powerful than fast-twitch fibres, which means they aren’t the best for hypertrophy (increasing the size of the muscle tissue).

Fast-twitch fibres are all about movements that require short bursts of energy. They are the powerful fibres, but they fatigue much quicker than slow-twitch fibres. These are the ones that will contribute to hypertrophy.

So in real life, your slow-twitch fibres will be engaged throughout most movements, but it’s only when you need to do something with force that your fast-twitch fibres are required and all units will be engaged.

It’s important to understand that you can’t isolate strength and muscle mass from one another – there is a clear correlation between the two.

However, depending on your goals (strength or muscle mass), there are distinct differences in the conditions in which each of them thrive.

If you want to build strength, you’ll need to be engaging all units at the same time – and the best way to do this is: lift heavy.

For building muscle mass, you need to look at protein degradation. As you lift, protein breaks down in your muscles and then repairs itself in recovery. To achieve maximum protein degradation, you’ll need to lift heavy for a high amount of repetitions. Lifting heavy at fewer reps will still result some level of protein degradation but not nearly as much.

Why does this matter?

It’s important to understand the relationship between muscle mass and strength, because it will determine exactly how you approach your goals in the gym.

To increase muscle mass, the ideal method for hypertrophy is lifting a medium weight, around 67-85% of your 1 RM (the heaviest weight you could lift for 1 rep), for 6-12 reps and 3-5 sets. You’ll also need to keep rest periods short, only resting for about 30-90 seconds.

To increase strength, it’s best to lift real heavy – more than 85% of your 1RM. You’ll also need to lift less than 6 reps, with 1-6 sets and take longer breaks in between (about 2-5 minutes).

While muscle mass and strength go hand-in-hand in many ways, it’s important to understand how they can thrive in different conditions so you can target your workouts according to your goals.

Virgin Active National PT Manager and sports science coach, Alex Davies, also says that while your muscles can be trained through specific exercises, one of the major contributions to muscle building and muscular strength is an individual’s genetics and somatotype and structure (the way your body is shaped).

“The body is a very complicated bit of machinery and the way you are made up has a huge contribution to the way your muscles work. Arnold may not be the strongest athlete but he had perfect symmetry (somatotype) to look the way he did. And some powerlifters who are extremely strong don’t. Pure strength and muscle building can be achieved by all but everyone is different and even if you have the same workout routine you most likely won’t develop in the same way in relation to strength and muscle mass.”